Iptacopan is a small-molecule factor B inhibitor previously investigated as a potential treatment for the rare blood disease paroxysmal nocturnal hemoglobinuria (PNH) by inhibiting the complement factor B.[A262566] Factor B is a positive regulator of the alternative complement pathway, where it activates C3 convertase and subsequently C5 convertase.[A262581] This is of particular importance to PNH, where one of the disease hallmarks is the mutation of the PIGA gene. Due to this mutation, all progeny erythrocytes will lack the glycosyl phosphatidylinositol–anchored proteins that normally anchor 2 membrane proteins, CD55 and CD59, that protect blood cells against the alternative complement pathway.[A262586] Additionally, iptacopan has the benefit of targeting factor B, which only affect the alternative complement pathway, leaving the classic and lectin pathway untouched for the body to still mount adequate immune responses against pathogens.[A262581] On December 6th, 2023, Iptacopan under the brand name Fabhalta was approved by the FDA for the treatment of adults with PNH. This approval was based on favorable results obtained from the phase III APPL-PNH and APPOINT-PNH studies, where 82.3% and 77.5% of patients experienced a sustained hemoglobin improvement without transfusions respectively.[L49116]
Iptacopan is indicated for the treatment of adults with paroxysmal nocturnal hemoglobinuria, for the reduction of proteinuria in adults with primary immunoglobulin A nephropathy (IgAN) at risk of rapid disease progression, and for the treatment of adults with complement 3 glomerulopathy (C3G), in order to reduce proteinuria.[L49066] In Canada it was approved for the treatment of adults with paroxysmal nocturnal hemoglobinuria who have hemolytic anemia. [L52610]
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